[llvm] [CodeGen] Fix `MachineModuleInfo`'s move constructor to be more safe with `MCContext` ownership. (PR #104834)

[weiwei chen via llvm-commits]

weiweichen wrote:

> @weiweichen @arsenm #105541 addresses the issues raised in the review here. If it proves challenging to merge due to `MCContext` management issues, we can merge only the first two items on the list regarding MMI's constructors. Let me know what you think.

@matinraayai, the changes in https://github.com/llvm/llvm-project/pull/105541 makes sense to me that it reflects the design change you suggested here as well. You did mention that the PR is WIP. I'm wondering how soon do you expect it, or at least the first 2 parts to get merged? (selfishness, I do really want the move constructor's bug fixed as soon as possible, either with a small patch or changing the way how MMI is used so that the move constructor is irrelevant with your PR 🙏)

https://github.com/llvm/llvm-project/pull/104834